CHAPTER XX
THE TESTING OF PAPER-TRANSPARENCY AND OPACITY-
DURABILITY AND STORAGE OF PAPER
THERE are a great many features which require to be considered in the testing
of paper as usually carried out at the mill or in the mill laboratory. We have
no intention of trespassing on the sphere of scientific research, or of describing
intricate processes, but simply to give such information as will be readily
understood and ample for commercial purposes.
In the making of all papers it is obvious that some standard for quality must
be aimed at, and before going further we must define what we mean by quality.
This expression as applied to paper is capable of a very wide definition;
literally, a paper of 'high-class quality' is one made by hand from the best
materials, such as new rags; sized by hand, loft-dried and possibly plate-glazed,
and, in fact, a paper of superlative excellence.
In the broad sense of the term, however, a paper may be of excellent quality,
no matter what its composition, provided that it is eminently suited for the
purpose for which it is to be used.
Newsprint, for instance, may be described as of very high-class quality,
and the term may be perfectly correct and logical, though it cannot be said
that newsprint, as paper, is of high quality.
Therefore, in testing or judging quality, some standard is necessary for
comparison, and as a basis on which to found a judgment. This basis, as between
the paper-maker and his customer, is generally defined in terms of price and
a certain sample to be matched, this sample being mutually agreed upon at
the time the order is placed.
It often happens, however, that a prospective customer sends a sample
and wishes to know the price at which it can be matched. Occasionally, too,
instead of a sample, a general indication of the kind of paper required is given.
If the paper supplied is a good match to the sample, taking into consideration the
price asked for it, the customer may consider the paper to be of 'good quality'.
Therefore, in testing paper, quality must be taken as a comparative term, all the
characteristics of the paper being placed against those of the sample individually.
For this reason it is necessary to be able to test a sample and ascertain its
composition, etc., before submitting an estimate of price, and, later, for the
purpose of being able to match it accurately.
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